IL-17及其相关细胞因子在腹型过敏性紫癜患儿外周血和肠黏膜中的变化

Changes of IL-17 and related cytokines in peripheral blood and intestinal mucosa of children with abdominal Henoch-Schonlein purpura

背景肠黏膜屏障的损伤、免疫系统紊乱可能是腹型过敏性紫癜(henoch-schonlein purpura, HSP)的重要发病机制之一,然而免疫因子与肠黏膜屏障损伤的关系尚不清楚.目的探讨外周血、肠黏膜白细胞介素-17(interleukin-17,IL-17)及其相关细胞因子的变化在腹型HSP发病机制中的作用,以及了解肠道菌群失调与腹型HSP发病机制的关系.方法选取26例急性期腹型HSP患儿为观察组, 16例健康体检儿童为健康对照组,收集两组儿童外周血、粪便标本;选取20例接受胃镜检查的急性期腹型HSP患儿为病例组,8例胃镜检查无明显黏膜病变的儿童为对照组,收集两组儿童十二指肠黏膜组织.采用流式细胞术检测外周血单个核细胞中辅助性T细胞-17(Th17)、细胞毒性T细胞-17(Tc17)细胞比例;ELISA检测血浆IL-17、IL-6、IL-23、γ-干扰素(IFN-γ)细胞因子含量;HE染色观察十二指肠黏膜活检组织病理改变;RT-PCR及免疫组化法检测十二指肠黏膜IL-17、IL-6、IL-23、IFN-γ mRNA及蛋白表达水平;细菌16S rDNA法检测肠道粪便中双歧杆菌、大肠杆菌的数量.结果观察组Th17与Tc17细胞比例均较健康对照组显著增高(P<0.05).观察组血浆IL-17、IL-6、IL-23水平均较健康对照组显著增高(P<0.05).病例组十二指肠黏膜组织病理改变主要为非特异性慢性炎症,部分可见血管炎性病变.病例组十二指肠黏膜IL-17、IL-6、IFN-γ mRNA及蛋白表达水平较对照组显著增高(P <0.05).观察组双歧杆菌数量、双歧杆菌/大肠杆菌比值较健康对照组显著下降(P<0.05).结论 IL-17及其相关细胞因子参与了腹型HSP患儿全身及肠黏膜局部的炎症反应,肠道菌群失调可能促进IL-17介导的炎症反应过程.与腹型HSP的发病及肠黏膜屏障损伤有关.

BACKGROUND Intestinal mucosal barrier injury and immune system disorder may be important in the pathogenesis of abdominal Henoch-Schonlein purpura(HSP). However,the relationship between immune factors and intestinal mucosal barrier injury remains unclear.AIM To investigate the role of changes of interleukin-17(IL-17) and its related cytokines in peripheral blood and intestinal mucosa in the pathogenesis of abdominal HSP, and to analyze the relationship between intestinal dysbacteriosis and the pathogenesis of abdominal HSP. METHODS Twenty-six children with acute abdominal HSP were included into an observation group and 16 healthy children were included into a healthy control group. Peripheral blood and fecal samples were collected from subjects of the two groups. Twenty children with acute abdominal HSP who underwent gastroscopy were selected as a case group, and eight children without obvious mucosal lesions were selected as a control group. The duodenal mucosal tissues of the two groups were collected. Flow cytometry was used to detect thepercentages of Th17 cells and Tc17 cells in peripheral blood mononuclear cells(PBMCs). ELISA was used to detect the contents of IL-17, IL-6, IL-23, and IFN-γ in plasma. HE staining was used to observe the pathological changes in the duodenal mucosa. RT-qPCR and immunohistochemistry were used to detect the m RNA and protein expression levels of IL-17, IL-6, IL-23, and IFN-γ in the duodenal mucosa, respectively. Bacterial 16 S r DNA was used to detect the number of Bifidobacterium and Escherichia coli in feces. RESULTS The percentages of Th17 and Tc17 cells in the observation group were significantly higher than those in the control group(P < 0. 05). Plasma concentrations of IL-17, IL-6, and IL-23 in the observation group were significantly higher than those in the healthy control group(P < 0. 05). The pathological changes in the duodenal mucosa in the case group were non-specific chronic inflammation, with vascular inflammatory lesions observed in some cases. The expression of IL-17, IL-6, and IFN-γ m RNAs and proteins in the duodenal mucosa in the case group were significantly higher than those in the control group(P < 0. 05). The quantity of Bifidobacterium and Bifidobacterium/Escherichia coli ratio in the observation group were significantly lower than those in the healthy control group(P < 0.05).CONCLUSION IL-17 and its related cytokines are involved in systemic and intestinal mucosal inflammation in children with abdominal HSP. Intestinal dysbacteriosis may promote the IL-17-mediated inflammatory reaction, which is related to the pathogenesis of abdominal HSP and intestinal mucosal barrier injury.